) and the other with relatively higher MeHg concentrations (0.096-0.220 µg g -1 ). Trout elevated in MeHg had a terrestrial carbon signature and fed at a higher trophic level than trout with low MeHg concentrations. The strontium: calcium ratio in the otoliths of two fish revealed that a trout with low MeHg values had lived in the sea for part of its life, whereas a trout with higher MeHg concentration had lived solely in the river. Sea-running trout were eating prey of marine origin, whereas the riverresident fish were consuming prey at a higher trophic level in the food web, which may result in markedly different MeHg concentrations in these fish.